FIELD OF THE INVENTION:

[001] The present invention broadly relates to non-toxic disinfectants. More specifically, the invention relates to light stable, environment-friendly antimicrobial disinfectants and sanitizer compositions with neutral pH, comprising of active metal ions and method of preparing the same.

BACKGROUND OF THE INVENTION

[002] Regular sanitization and disinfection of the surface and premises we work upon is the need of the hour in the Covid era. However, the traditional chemicals used for disinfection such as the benzothiazoles, parabens, hypochlorites, peroxides, quaternary ammonium compounds etc. may not be safe and are toxic for long term usage over a period of time. Thus, there is a need for safe and benign disinfectants for regular usage. Silver compounds have been known for a long time for their natural anti-microbial activity and have been used as anti bacterial agents in various compositions, where germs do not tend to survive in its presence and do not show side effects on the human body.

[003] It is reported that the usage of water-soluble silver compounds as effective antimicrobials, generally requires their content to be more than 10% in these formulations. Prolong usage of these formulations may lead to the accumulation of silver in the human body, with subcutaneous accumulation as well, which in turn might lead to skin discoloration. Considering these factors, there is the need of non-toxic formulations with near neutral pH, effectively able to neutralize microorganisms without having any environmental hazards and non-toxic to the skin.

[004] References have been made to the following literature:

[005] AU2005322839 relates to a colorless composition comprising metal particles (e.g., silver nanoparticles) and water, wherein said particles comprise an interior of elemental metal (e.g., silver) and an exterior of metal oxide (e.g., one or more silver oxide(s)). The silver nanoparticles composition disclosed in the prior art is a complex one where the toxicity of nanoparticles is a severe issue. In the present invention there is a gradual release of silver with the complexing agent, where the silver ions are bioavailable and yield a stable and highly effective colorless composition.

[006] KR20120035689 relates to a formulation comprising Ag atoms of the resulting nanoparticle size with secondary purified water and 3% of 35% hydrogen peroxide and also chitosan, vitamin C with concentrations of silver at 1-100 ppm. The resultant formulation in the prior art is a toxic silver colloidal silver peroxide solution for the production of ionic solution and unsafe to the human body.

[007] JP5693470 relates to silver ion-based disinfectant composition exhibiting a synergistic effect in isotonic or hypertonic media when combined with low concentrations of menthol, provided that silver ions are typical for disinfectant purposes, where it is present at a lower concentration than is used in.

[008] CA2500836 discloses a pharmaceutical composition, comprising of a pharmaceutically acceptable carrier; and a silver-containing material in the pharmaceutically acceptable carrier, wherein the pharmaceutical composition comprises from about 0.001 weight percent to about 50 weight percent of the silver-containing material.

[009] US7311927 relates to a liquid antiseptic and cleanser having improved long-term stability including at least the following principal ingredients: deionized water; silver ion, polypectate, and ethylenediaminetetraaceticacid (EDTA). Presently preferred embodiments of the technology also include glycerine; 1,2-propanediol (a.k.a. propylene glycol); at least one surfactant from any of the families of alkylsulfates, sulfonates, alkanolamides, betaines, amine oxides, sarcosinates and sulfosuccinates; and a buffering compound sufficient to achieve a pH value within a range of 7.2 to 7.8. The silver salts used in the prior art comprises chelated silver ions generated using aqueous ammonium which are not very stable due to a gradual decomposition of the polypectate molecules or/and the gradual formation of extraneous compounds having greater affinity for the silver ions than the polypectate molecules. The greater the heat or the greater the energy of the incident light, the more rapid the decomposition. But the present invention discloses a heat and light stable composition with a prolong stability.

[0010] US 10251392 relates to methods and compositions for antimicrobial devices comprising salts or complexes of silver, copper or zinc. In one aspect, the metal salts may comprise metal salts of saccharin, acesulfame, long chain fatty acids, and alkyl dicarboxylic acids. The silver salts used in the prior art comprise organic silver molecules which have solubility issues, but the present invention discloses a stable, aqueous composition with long lasting effects.

[0011] It is evident that despite the widespread use of silver as an antibacterial agent, the silver solutions are generally light sensitive formulations comprising of silver nanoparticles or in the form of zeolites. These solutions have a limited stability and pH concerns, therefore limited shelf life. Accordingly, there is a need to create stable and light insensitive formulations with a potent anti microbial activity. The methodology of the present invention results in a potent disinfectant composition with neutral pH and instant kill activity, besides being cost effective, light stable and environmental friendly.

[0012] The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

OBJECT OF INVENTION:

[0013] The principal object of the embodiments herein is to overcome the drawbacks in the prior art and provide a composition for light stable and environmental friendly disinfectants and sanitizers, with neutral pH comprising of active metal ions with bio polymer and chelating agent and method of preparing the same.

SUMMARY OF THE INVENTION:

[0014] The present invention attempts to overcome the problems faced in the prior art, and discloses a composition which can effectively neutralize microorganisms on the hard surfaces by providing for a stabilized, non-toxic, antimicrobial aqueous disinfectant comprising of silver salts with bio polymer and chelating agent.

[0015] Accordingly, the embodiments in the present invention relate to a non-toxic disinfectant composition with neutral pH, comprising of active metals salts for disinfection and method of preparing the same. The resultant formulation is colourless and odourless. [0016] In a preferred embodiment the present invention discloses an antimicrobial disinfectant composition comprising: a silver salt 0.1-2% (w/v); a chelating agent 1-10% (w/v); and a polymer 1-10% (w/v); wherein the pH of the disinfectant composition is adjusted to greater than or equal to 7 and less than or equal to 9. The pH adjusters such as phosphate buffers, sodium and potassium hydroxide may be used to maintain the pH around neutral.

[0017] In another embodiment the present invention discloses an antimicrobial disinfectant composition wherein the silver salt is selected from a group comprising water soluble silver salts such as silver nitrate, silver chloride, silver fluoride, silver suphate/sulfide, silver acetate, and silver lactate. Further, the chelating agent is selected from a group comprising of ethylenediaminetetraacetic acid (EDTA) salts such as disodium EDTA, sodium calcium edetate, and tetrasodium EDTA, dimercaptosuccinic acid, dimercapto-propane sulfonate, salts of diethylene triamine pentacetic acid and dimercaptol, but not limited to; where the chelating agents work by binding to metals, with the role is to keep the silver ions bound and prevent its oxidation. The polymer in the composition is selected from a group comprising hydrophilic bio polymers such as poly vinyl pyrrolidone, poly ethylene glycol, poly vinyl alcohol and combinations thereof, but not limited to.

[0018] In a preferred embodiment the present invention discloses a process of preparing an antimicrobial disinfectant composition, comprising the steps of: a) weighing out 70-90% of the water required in the container and deoxygenating it using nitrogen gas; b) preparing the matrix by addition of chelating agents in the deoxygenated water obtained in step a; c) adding silver salt to the solution obtained in step b); and d) adding the bio-polymer to the composition obtained in step c) with gentle stirring and making up the final volume with water. Further, the pH adjusters are added to maintain the pH in the range of 7 to 9.

[0019] In yet another embodiment the present invention discloses the method wherein the polymer added in the range 1-10 %, makes hydrogen bonds with the surface to further improve disinfectability and to provide residual stability in the composition.

[0020] In still another embodiment the present invention discloses an aqueous antimicrobial disinfectant composition, which may comprise powdered form, tablet or capsule containing the antimicrobial powder, or antimicrobial solutions in the form as aerosols, infusions, sprays, mist, drops, or one or more liquids formulations, but not limited to. Further, the disinfectant shows instant kill activity with decontaminating the surface within 30 seconds of exposure time, wherein the surface is a hard surface.

[0021] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present invention and are therefore not to be considered for limiting its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the leftmost digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present invention are now described, by way of example, and with reference to the accompanying figures, in which:

[0023] Fig. 1 illustrates the methodology for the preparation of the composition, in accordance with an embodiment of the present invention;

[0024] Fig. 2 illustrates the ASTM B-117 salt spray test results with no red or white rust observed in the stainless steel panels treated with the anti microbial composition even after 48 hrs, in accordance with an embodiment of the present invention;

[0025] Fig. 3 illustrates the typical zone of inhibition in anti microbial study for the composition, in accordance with an embodiment of the present invention;

[0026] Fig. 4 illustrates the absorption data for the storage stability test for the composition, in accordance with an embodiment of the present invention; and [0027] Fig. 5 illustrates the typical zone of inhibition in anti microbial study with the composition before and after storage for 14 days, in storage stability test, in accordance with an embodiment of the present invention.

[0028] The figure depicts embodiments of the present invention for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

[0029] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure. Further, the phraseology and terminology employed in the description is for the purpose of description only and not for the purpose of limitation.

[0030] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, apparatus, system, assembly, method that comprises a list of components or a series of steps that does not include only those components or steps but may include other components or steps not expressly listed or inherent to such apparatus, or assembly, or device. In other words, one or more elements or steps in a system or device or process proceeded by “comprises... a” or “comprising .... of’ does not, without more constraints, preclude the existence of other elements or additional elements or additional steps in the system or device or process as the case may be. Besides, the use of “comprising”, “consisting” or “including” also contemplates embodiments that “consist essentially of’ or “consist of’ the recited formulation and steps of preparation of the formulation.

[0031] The present invention relates to an anti microbial composition which can effectively neutralize microorganisms on the hard surfaces by providing for a light stable, antimicrobial aqueous disinfectant comprising of silver salts with bio polymer and chelating agent. The invention further discloses a non-toxic disinfectant composition with neutral pH, comprising of active metal salts for disinfection and method of preparing the same. The resultant formulation is colourless and odourless. The solid content in the aqueous formulation comprises only ~ 6-7 % wt/volume. The bio-polymers and chelating agents are widely used materials in the food and cosmetics industry and are known to be of low acute toxicity when administered by the intravenous route in humans or by the oral and intravenous routes in various species of laboratory animals. They are not known to bio-accumulate or cause any eco-toxicity.

[0032] Reference may be made to Figure 1 illustrating the methodology for the preparation of the composition, in accordance with an embodiment of the present invention. In a preferred embodiment the present invention discloses a process of preparing an antimicrobial disinfectant composition, comprising the steps of: a) weighing out 70-90% of the water required in the container and deoxygenating it using nitrogen gas; b) preparing the matrix by addition of chelating agents in the deoxygenated water obtained in step a; c) adding silver salt to the solution obtained in step b); and d) adding the bio-polymer to the composition obtained in step c) with gentle stirring and making up the final volume with water. Further, the pH adjusters are added to maintain the pH in the range of 7 to 9. (Figure 1).

[0033] Reference may be made to Figure 2 illustrating the ASTM B-117 salt spray test results with no red or white rust observed in the stainless steel panels treated with the anti microbial composition even after 48 hrs, in accordance with an embodiment of the present invention;

[0034] Reference may be made to Figure 3 illustrating the typical zone of inhibition in anti microbial study for the composition, in accordance with an embodiment of the present invention;

[0035] Reference may be made to Figure 4 illustrating the absorption data for the storage stability test for the composition, in accordance with an embodiment of the present invention; and

[0036] Reference may be made to Figure 5 illustrating the typical zone of inhibition in anti microbial study with the composition before and after storage for 14 days, in storage stability test, in accordance with an embodiment of the present invention. [0037] In an embodiment the present invention discloses an antimicrobial disinfectant composition comprising at least one or more antimicrobial metal in a concentration sufficient to provide anti-microbial effect; a chelating agent; and a hydrophilic bio-polymer in distilled water.

[0038] In a preferred embodiment the present invention discloses an antimicrobial disinfectant composition comprising: a silver salt 0.1-2% (w/v); a chelating agent 1-10% (w/v); and a polymer 1-10% (w/v); wherein the pH of the disinfectant composition is greater than or equal to 7 and less than or equal to 9. The pH adjusters such as phosphate buffers, sodium and potassium hydroxide may be used to maintain the pH around neutral.

[0039] In another embodiment the present invention discloses an antimicrobial disinfectant composition wherein the silver salt is selected from a group comprising water soluble silver salts such as silver nitrate, silver chloride, silver fluoride, silver sulphate, silver acetate, silver lactate and silver carbonate, but not limited to. Further, the chelating agent is selected from a group comprising of ethylenediaminetetraacetic acid (EDTA) salts such as disodium EDTA, sodium calcium edetate, and tetrasodium EDTA, dimercaptosuccinic acid, dimercapto-propane sulfonate and dimercaptol, but not limited to; where the chelating agents work by binding to metals, with the role is to keep the silver ions bound and prevent its oxidation. The polymer in the composition is selected from a group comprising hydrophilic bio polymers such as poly vinyl pyrrolidone, poly ethylene glycol, poly vinyl alcohol and combinations thereof, but not limited to.

[0040] In yet another embodiment the present invention discloses the method wherein the polymer added in the range 1-10 %, makes hydrogen bonds with the surface to further improve disinfectability or to provide residual stability in the composition.

[0041] In still another embodiment the present invention discloses an aqueous antimicrobial disinfectant composition, which may comprise powdered form, tablet or capsule containing the antimicrobial powder, or antimicrobial solutions in the form as aerosols, infusions, sprays, mist, drops, or one or more liquids formulations, but not limited to. Further, the disinfectant shows instant kill activity with decontaminating the surface within 30 seconds of exposure time, wherein the surface is a hard surface. [0042] Accordingly, the silver content in the composition is measured by standard titration with thiocyanate ion. The proportion of biopolymer is carefully chosen so as to yield maximum wettability on the surface and formation of a thin film that would be almost invisible when fogging surfaces.

Examples:

[0043] Example 1: In 1 liter water, 12.5 g of the sodium salt of EDTA was dissolved and followed by the addition of 100 mg of the silver nitrate salt. This resulted in formation of a clear solution, to which 5 g of poly vinyl pyrrolidone (PVP) was added and the solution was stirred well, and, pH was brought up to a neutral level. This resulted in a light insensitive and stable solution as the silver ion content when measured over a period of several weeks, remained constant around 56 ± 2 ppm by standardized titration methods with thiocyanate ion. The procedure consisted of titration of silver(I) with a standard potassium thiocyanate (KSCN) solution with the reaction as:

[0044] The titration was carried out in an acidic solution. When the silver (I) precipitated as white silver thiocyanate, the first excess of titrant and the iron (III) indicator reacted and formed a soluble red complex. Concentrated nitric acid was then added to prevent hydrolysis of the ferric ammonium sulphate which had been used as an indicator. The standardized thiocyanate solution was then added drop by drop from the burette into the silver sample until the faint brownish color did not disappear under vigorous stirring. The volume of thiocyanate, at the point when the color first becomes permanent was noted and the normality of the silver in the formulation was calculated. The observed sensitivity was approximately ± 2 ppm of predicted values and validated with standard testing consisting of Atomic Absorption Spectroscopy.

[0045] Example 2: ASTM E-2315 Test was used to assess the in vitro reduction of a microbial population of test organisms after exposure to the disinfectant composition (test material), which was a time kill study of the sample on E. coli. In this, a pure culture of E. coli was streaked on Soyabean Casein Digest Agar plates and incubated at 37° C for up to 2 days. Following incubation, the surface of agar plate was scraped and the growth suspension was adjusted to a concentration of 106 cfu/ml. Test and control substances were dispensed in identical volumes to sterile test tubes. Independently, Test and Control substances were inoculated with the test microorganism, mixed and incubated. Control suspensions were immediately plated to represent the concentration present at the start of the test, or time zero and at the conclusion of each contact time; a volume of the liquid test solution was neutralized. Dilutions of the neutralized test solution were placed on to appropriate agar plates and incubation temperatures to determine the surviving microorganisms at the respective contact times and reductions of microorganisms were calculated by comparing initial microbial concentrations to surviving microbial concentrations. The sample showed 99.9999% reduction on exposure to Escherichia coli when exposed for just 15 seconds (Table 1), thereby instant killing activity of the composition as compared to the control.

[0046] Table 1: Experimental Results for ASTM E-2315 Test

[0047] Example 3: ATP TEST: ATP test was done for rapidly measuring the actively growing microorganisms through detection of adenosine triphosphate, or ATP, which gave the direct measure of biological concentration and health. An ATP reading of 0-20 generally indicated an ultraclean to clean surface.

[0048] A standard ATP meter was used for the measurement of the surfaces after the spray of disinfectant compositions with and without biopolymer. After spraying of above solution on various surfaces such as cardboard, wood, glass, SS and plastic ATP readings of around 10 to 15 were noted. The readings remained in the same range even 30 days after the application. However in the case where the bio-polymer was not mixed into the formulation - the ATP readings were higher after the 30 days interval, thereby showing the presence of contaminants. Especially on a working table made of wood and having a lot of mechanical abrasion, when treated with the “without polymer composition”, a rapid increase in the readings to about 30 to 40 Relative Light Units (RLU’s) after 30 days was recorded, showing the presence of contaminants. These results showed that addition of the bio-polymer conferred the disinfectant the ability to bind, which in turn resulted in prolonged anti microbial activity of the disinfectant on the surface.

[0049] Example 4: ASTM B-117 salt spray test, a corrosion test was done to provide corrosion resistance information on metals and coated metals. The NaCl concentration (w/v %) was set at 4.0 - 6.0 and the saturation air temperature was 47 + 0.1 C, pH 6.5 - 7.2 6. Temp, of Salt Water Compressed Air (kg/cml + 0.1 7. Temp, of chamber 35 + 0.1. No Red or White rust was observed in the stainless steel panels treated with the anti microbial composition even after 48 hrs; however untreated panels in IB control got few red rust spots after 48 hrs (Figure 2). The results of ASTM B-117 salt spray test stated that the composition was corrosion resistant.

[0050] Example 5: Neutralizer Test: Disinfectant composition comprising 0.02% (w/v) Silver salt, 3% chelator and 1% polymer was checked for the antimicrobial efficacy on Stainless Steel (SS) substrates. For the SS study the test culture used was S. aureus (ATCC 6538) and the neutralizer used was the Dey Engley Neutralizing Broth (DENA broth). The culture was incubated at 37°C for 24 h. The media and reagent used was the Soyabean Casein Digest Agar.

[0051] DENA broth neutralizes a broad spectrum of antiseptics and disinfectants including quaternary ammonium compounds, phenolics, iodine and chlorine preparations, mercurials, formaldehyde and glutaraldehyde. In the results, neutralizer effectiveness was monitored. In the Test sample A as compared to control (Table 2). The results were given in percentages only. The Neutralizer toxicity and test organisms’ viability was also measured and verified.

[0052] Table 2: Results from the Neutralizer test:

[0053] From the observations, 99.9999% reduction for antimicrobial activity against S. aureus bacteria was observed on the SS substrate treated with the composition (Table 3).

[0054] Table 3: Results showing reduction of bacteria on the ss surface, with Number of Bacteria on Untreated SS Substrate: 4.2 x 10 ⁶ cfu/ml

[0055] Further, Zone of inhibition for S. aureus and P. aeruginosa was detected as 24.78 mm and 24.99 mm respectively (Table 4 and Figure 3). The results thus stated the neutralizer effectiveness and anti-microbial disinfectant activity of the composition.

[0056] Table 4: Analysis Results for Zone : Concentration of sample: Neat

[0057] Example 6: Skin Safe Test: The disinfectant sample was applied on the hands of five volunteers after the consented approval. No rashes, itchiness, irritation or reddening was observed on the skin of the volunteers even after 5 hours of application. The disinfectant composition thus is a skin friendly composition, causing no harm even in case of accidental spillage.

[0058] Table 5: Skin safe test results with the Rating Scale as : 0-2- No effect; 3-5 - slight; 6 -8 - moderate; 9-10 very high

[0059] Example 7: Interim Data: The interim method includes an efficacy assessment of the coated coupons following exposure to certain chemical solutions/ mechanical abrasion. The motivation is to check for supplemental residual efficacy when the disinfection events are well spaced out. The test method provides for the evaluation of durability and the baseline efficacy of these treated surfaces against Staphylococcus aureus and Pseudomonas aeruginosa·, the method can be adapted for additional microbes and viruses. A minimum 3 log reduction of test microbes within 1-2 hours is the required level of performance. The USEPA interim method to support efficacy requirements for the registration of coatings applied to surfaces that are intended to provide residual antimicrobial activity for a period of weeks and are designed to be supplements to standard disinfection practices.

[0060] In brief, the test method comprised of two parts: 1) chemical treatment and abrasion, and 2) product efficacy. The method used 1” x 1” brushed stainless-steel carriers coated with the antimicrobial chemical and uncoated control carriers. Carriers were exposed to 10 cycles of chemical treatment/abrasion in order to support a 1-week duration label claim of residual activity. Testing could be scaled up to support longer claims up to 4 weeks. The chemical exposure and abrasion processes were intended to represent a degree of normal and relevant physical wear, as well as reproduce potential effects resulting from repeated exposure of antimicrobial coated surfaces to three different biocidal materials (chemical solutions) as well as the impact of dry abrasion. Under controlled environmental conditions, the carriers received a 20 μL mixture of the test organism and soil load. Following a recommended 1-2 hour contact time, the carriers were neutralized and the number of viable microorganisms was determined quantitatively. The log reduction (LR) in the viable test organisms on exposed carriers was calculated in relation to the viable test organisms on the unexposed control carriers. The impact of the chemical exposure and abrasion on product efficacy was also determined by comparing carriers with and without coating not exposed to chemical treatment and abrasion.

[0061] The chemical exposure/abrasion cycle for a single chemical (Treatments A, B, and C) was done using a wetted sponge with a weight of 454 g. The dry abrasion treatment (Treatment D) was done using a dry sponge without additional weight to perform sixteen single passes across the carriers. 10 abrasion cycles were performed (80 single passes across the surface of the carrier for treatments A, B, and C; 160 single passes across the surface of the carrier for Treatment D with appropriate dry times between abrasion cycles on Lot 1 to support a 1-week residual claim. The number of abrasion cycles performed was made for residual claims of 4 weeks. The results were promising in that the mechanical abrasion in the wet and dry states showed a 4 log reduction. In the presence of cleaning chemicals also there was a good antimicrobial ability.

[0062] Table 6: Results with test sample

*taken as zero for calculation [0063] As per the above observations it was concluded that the test sample showed 4 log reductions and (99.995%) bactericidal activity when compared to the without coated carrier specimen both in the wet and dry.

[0064] For the coated specimen treated with 3 chemical treatments

-Sodium hypochlorite solution (A) compared with uncoated specimen showed 96.66% reduction. There were no colonies (growth) observed on the coated sample whereas for the uncoated there were 30 colonies observed.

- 6% hydrogen peroxide solution (B) compared with uncoated specimen showed 50 % reduction.

- 2% Benzalkonium Chloride solution (C) and compared with uncoated specimen showed 99.47 % reduction. No colony (growth) was observed on the coated sample whereas for the uncoated 190 colonies were observed.

[0065] Example 8: Storage Stability Test: The samples were held in an oven at 54°C for 14 days. No visible clumping or deterioration of the product was observed that would interfere with its disinfectant ability. The absorption data for the storage stability test is shown in Figure 4. The zone of inhibition was also checked for the solution kept for 14 days in the oven and slight change in the zone diameters was observed (possibly due to loss of some water) but the results confirmed the intact disinfection ability of the solution even after 14 days (Table 7 and Figure 5).

[0066] Table 7 : Analysis Results for Zone: with sample stored for storage stability test for 14 days [0067] Example 9: Particle Analysis: The particle analysis was done using a Laser Diffraction (LD) analyzer, a particle size analyzer that used three precisely placed red laser diodes to accurately characterize particles by utilizing Mie compensation for spherical particles and the proprietary principle of Modified Mie calculations for non-spherical particles. The resolution of the tool was from 0.01 to 2,800 μm. Any light obscuration depicts the presence of nanoparticles in the composition. The results did not show any light obscuration and no particles were detected in the range. The experiments were repeated thrice and the absence of any light obscuration thereby confirmed that there was no nanoparticle contamination in the disinfectant composition.

[0068] Table 8: The different parameters of the composition studied are summarized in the table. [0069] In accordance with advantages of the present invention as compared with the existing formulations, the present invention is to provide a big change in the field of disinfectants and sanitizers. The formulations were prepared with typically 0-2% of the salts and then the biopolymer was added to impart the “sticking” property so that the formulation continues to have a long-lasting residual efficacy. This is a low cost, light stable formulation with results showing instant eradication of pathogens from the hard surface such as stainless steel, plastic, glass etc. Besides, being a colorless composition, it eliminates the after usage concern of stains. Further, the composition may comprise the form of a liquid formulation, aerosol, foam, spray, powdered form or pellets, where it can be formulated to a higher concentration of up to 10:1. Conventional and non-conventional methods may be used for application including but not limited to: roll coating, dipping, spraying, or rotational tumbling. The silver EDTA powder after the removal of unwanted anions and cations by ion exchange can be isolated, which can further be stored as a powdered disinfectant, thereby lowering the plastic waste and transportation cost.

[0070] The silver-EDTA complex formed in the reaction has technical advantages over antimicrobial drugs and disinfectants. First, EDTA is a hexa-dentate molecule due to which, Ag ⁺ ions are tightly bound and delivered gradually. The high reactivity of the silver complex triggers elevated intracellular levels of reactive oxygen species (ROS) provoking the disruption of lipids, proteins and DNA, ending in cell death of the microbes. Secondly, since no specific antimicrobial target mechanism exists; thus, antimicrobial resistance is unlikely for such combinations. The water soluble bio polymers such as poly vinyl pyrrolidone (PVP) make hydrogen bonds with the surface due to which the anti bacterial activity remains for a longer time on the surface and thus in turn providing long residual activity of the disinfectant.

[0071] Advantages:

The present invention provides a

• pH neutral composition as compared to the acidic pH ones of the prior arts

• Light stable silver composition whereas the prior arts available are light sensitive formulations

• Heat resistant at least till 54 °C applied over a period of 14 days. • Stable coating having residual efficacy wherein the “coating” formed was not removed even with 4 weeks of simulated mechanical agitation using 3 types of cleaning chemistries

• Colorless composition so no concern of stains after use

• Composition may comprise the form of a liquid formulation, aerosol, foam, spray, where it is a scalable composition upto 10:1.

• Silver EDTA powder isolated as a powder after ion exchange, can be stored as powdered disinfectant, thereby lowering the plastic waste and transportation cost.

[0072] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein.

[0073] Although embodiments for the present invention have been described in language specific to structural features, it is to be understood that the present invention is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present invention. Numerous modifications and adaptations of the system/ component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present invention.